Put the almonds on a baking tray and toast them in the oven for 5–8 minutes until fragrant and lightly golden brown – start checking on them after 5 minutes as they can scorch quickly. Spread them out on a cold plate to cool completely, then tip into a food processor and pulse them until quite fine but not oily.2
Tear the bread into chunks and soak in cold water to cover for a couple of minutes. Squeeze out the excess water and add the bread to the almonds in the food processor.
Cut off a 10 cm piece of cucumber and set aside. Peel the rest of the cucumber (use the peel to infuse a jug of water if you like, page 158). Halve the cucumber lengthways and scoop out the seeds with a teaspoon, then chop the flesh roughly. Add to the food processor.
Add the garlic, olive oil, 1tablespoon vinegar, ¼ teaspoon salt and some pepper. Blend until smooth, adding a splash of cold water to thin a little if you like, but it’s best kept pretty thick.
Transfer the soup to a bowl or jug, cover and refrigerate for several hours to chill thoroughly. When ready to serve, taste the soup and add more salt or vinegar if it needs it. Cut the reserved cucumber into julienne strips.
Divide the soup between chilled bowls. Add a trickle of olive oil and finish with the cucumber julienne and toasted almonds, if using.
Tips and swaps:
Add salad leaves: If you have any slightly tired lettuce, rocket or watercress, you can toss the leaves into the soup before blitzing – simply tear off and discard the worst bits first.
Finish with grapes: Float a handful of seedless green grapes on each portion instead of the toasted almonds.